Li Chao, Ran Minyuan, Liu Jianwei, Wang Xiaoxiao, Wu Qingbing, Zhang Qiang, Yang Jing, Yi Feng, Zhang Heng, Zhu Jian-Kang, Zhao Chunzhao
Shanghai Center for Plant Stress Biology, CAS Center for Excellence in Molecular Plant Sciences, Chinese Academy of Sciences, Shanghai, China.
University of the Chinese Academy of Sciences, Beijing, China.
Front Plant Sci. 2022 Dec 12;13:1083438. doi: 10.3389/fpls.2022.1083438. eCollection 2022.
Protochlorophyllide oxidoreductase (POR) plays a key role in catalyzing the light-dependent reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide), and thus promotes the transit from etiolated seedlings to green plants. In this study, by exploring ethyl methanesulfonate (EMS)-mediated mutagenesis in NL-6 variety, we identified a mutant that displays faded green leaf and reduced chlorophyll (Chl) and carotenoid contents. Bulk segregant analysis (BSA) revealed that a mutation in gene is genetically associated with the faded green leaf of the mutant. Further study indicates that the mutant exhibits abnormal grana stacks and compromised conversion of Pchlide to Chlide upon illumination, suggesting the important role of in producing photoactive Pchlide. Totally three isoforms, including , , and are identified in NL-6 variety. Transcriptional analysis shows that the expression of all these three isoforms is regulated in light- and development-dependent manners, and in mature quinoa plants only isoform is predominantly expressed. Subcellular localization analysis indicates that CqPORB is exclusively localized in chloroplast. Together, our study elucidates the important role of CqPORB in the regulation of Chl biosynthesis and chloroplast development in quinoa.
原叶绿素酸酯氧化还原酶（POR）在催化原叶绿素酸酯（Pchlide）光依赖还原为叶绿素酸酯（Chlide）过程中起关键作用，从而促进黄化幼苗向绿色植物的转变。在本研究中，通过探索甲磺酸乙酯（EMS）介导的NL-6品种诱变，我们鉴定出一个突变体，其叶片呈现淡绿色且叶绿素（Chl）和类胡萝卜素含量降低。混合分组分析法（BSA）表明，一个基因的突变与该突变体的淡绿色叶片在遗传上相关。进一步研究表明，该突变体表现出异常的基粒堆叠，且光照后Pchlide向Chlide的转化受损，这表明该基因在产生光活性Pchlide中起重要作用。在NL-6品种中总共鉴定出三种POR同工型，包括CqPORA、CqPORB和CqPORC。转录分析表明，这三种同工型的表达均受光和发育依赖方式的调控，在成熟藜麦植株中仅CqPORB同工型占主导表达。亚细胞定位分析表明，CqPORB仅定位于叶绿体。总之，我们的研究阐明了CqPORB在藜麦叶绿素生物合成调控和叶绿体发育中的重要作用。
